America’s oldest suspension bridge pioneered technologies that were later used at the Brooklyn Bridge.

The Delaware Aqueduct is the sole survivor of the four suspension aqueducts built in America by John A. Roebling between 1848 and 1850. Though not the world’s first suspension bridgenotable precedents built on both sides of the Atlantic include James Finley’s Jacob’s Creek Bridge in Pennsylvania (1801), Thomas Telford’s Menai Suspension Bridge in Wales (1826; see here), Joseph Chaley’s Grand Pont Suspendu in Switzerland (1834), Charles Ellet Jr.’s Fairmount Bridge in Pennsylvania (1842) and the Wheeling Bridge in West Virginia (1849)it is the oldest wire cable suspension bridge still standing that retains most of its original structure. It is also the earliest extant example of the type of bridge that would secure John A. Roebling’s place in history.

Coal from northeastern Pennsylvania was transported on boats pulled through waterways on the Lackawaxen, Delaware, and Hudson rivers before reaching its final destination, the profitable markets of New York City. By the midnineteenth century, this method of shipping was too slow and unreliable, given the increasing competition from the burgeoning rail system. In 1847 R. F. Lord, chief engineer of the Delaware and Hudson Canal Company, accepted Roebling’s unconventional but economical proposal for two suspended aqueducts to span the Lackawaxen and Delaware rivers.

We may affirm absolutely that nothing great in the world has been accomplished without passion.

In 1898 the last boat passed through the Delaware Aqueduct, which was subsequently converted into a vehicular bridge. The National Park Service acquired it in 1980 and by 1986 had reconstructed the superstructure using Roebling’s original plans and specifications.

The Delaware Aqueduct consists of a waterway, or flume, flanked by towpaths on either side. The weight of the water is carried by two continuous main cables, each 8.5 inches (21.6 centimeters) in diameter and composed of 2,150 wires. The cables are draped from cast-iron saddles mounted on squat masonry towers, and carry four spans with lengths ranging from 131 to 142 feet (40 to 43 meters). The Lackawaxen Aqueduct, a half mile away and no longer standing, was constructed in a nearly identical manner. Structurally and operationally, the aqueducts were an unqualified success, slashing a full day from canal travel and saving thousands of dollars annually. John Augustus Roebling (1806-1869), the father of the modern suspension bridge, was gifted with a brilliant analytical mind, inexhaustible curiosity, and an iron will. German born, Roebling studied architecture at Berlin’s Royal Polytechnic Institute, as well as philosophy under Hegel, whose doctrine of selfrealization proved a powerful influence. He emigrated to the United States in 1831 to establish an agrarian community in Saxonburg, Pennsylvania. While working as a canal surveyor, Roebling witnessed an accident caused by a snapped hemp cable and had a breakthrough revelation about the superior strength of wire rope. By 1845 he had completed two prototypical suspension bridgesthe Allegheny Aqueduct over the Allegheny Canal and the Monongahela Bridge in Pittsburghthat would inform all his future designs. Roebling’s design for the Covington-Cincinnati Suspension Bridge (1866; later renamed the John A. Roebling Bridge) over the Ohio River was executed by his son, Washington. That project nurtured the father-son relationship that would prove critical to the completion of the Brooklyn Bridge (see here) sixteen years later.